BBC Sounds Music Radio Podcasts Hello from my cupboard again, it's day 7 and I've

done so many lateral flow tests now, I don't even make that noise when you do the throat

swab. What I have noticed though is that the red lines on my lateral flow tests to show

I'm positive are so thick and so red they're almost black which has really got me wondering

like what does the quality or the thickness or the colour of the line on the lateral flow

test actually tell you if anything and hopefully someone who can tell us and reassure me is

our Edwards who's an associate professor of biomedical technology at Reading University.

Hello. So what if anything can I tell from the thickness of the line on the strip?

There's two answers to that and the straight forward and simple and easy answer is that

these are tests which are intended to tell you whether there's virus present in this

swab that you take from your nose or throat or both and beyond that is not really supposed

to tell you anything so the simple answer is that if it's positive it's positive and

if it's negative it's negative but you made an interesting point you know the line does

get stronger or weaker and that can be due to different things it could be that there's

more virus on the swab it could be something else and so that's why we try not to focus

on that too much. Right because one of my pet theories was well because I've been reporting

on lateral flow tests for more than a year now maybe I'm just very good at doing the

swabbing and some of the people I know are less vigorous. So absolutely spot on that would

be one of the things and maybe even you've been getting better and better you know your

techniques improved and we do know that you know different times and for different people

there can be different amounts of virus in different locations too so that could be one

explanation. I see and in terms of infectiousness because I mean I went out for a walk today

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